Profilin gene expression and regulation in a temperature-sensitive breast cancer cell line: tsFT101

 The temperature-sensitive mutant cells (tsFT101) derived from a mouse mammary carcinoma cell line, FM3A, become multinucleated at a non-permissive temperature of 39°C. To further understand the molecular mechanism of such cytokinetic disturbance, we examined the expression of profilin, the main regulator of the transition of globular actin (G-actin) to filamentous actin (F-actin). RT-PCR analysis of mouse profilin cDNA from tsFT101 showed a point mutation (177 A → G) which was a wobble mutation causing no change in the encoded amino acid. The expression level of profilin mRNA was, however, diminished in cultured tsFT101 cells under non-permissive temperatures compared with wild-type FM3A cells in association with multinucleation. A stable transfection of profilin cDNA expression vector to tsFT101 cells prevented multinuclear cell formation when cultured at 39°C. In contrast, antisense profilin cDNA expression vector did not alter multinuclear cell formation. The primary cause of the cytokinetic disturbance of tsFT101 cells may be due to the diminished level of profilin gene expression. Received: 6 January 1997 / Received after revision and accepted: 17 April 1997     

Deregulated expression of<Emphasis Type="Italic"> KRAP</Emphasis>, a novel gene encoding actin-interacting protein,in human colon cancer cells

We have identified a novel gene, designated KRAP (Ki-ras-induced actin-interacting protein), encoding a protein of 1,259 amino acids with coiled-coil regions and transmembrane regions, from the cDNA library of human colon cancer HCT116 cells, as one of the genes upregulated by activated Ki-ras. While KRAP was rarely expressed in normal colon epithelium, deregulated constitutive KRAP expression was observed in some other colon cancer cells. In normal tissues, KRAP was strongly expressed in pancreas and testis. Anti-KRAP polyclonal antibodies detected endogenous KRAP as the molecular size of M_r 180,000, and immunofluorescence microscopy and cytochalasin E treatment revealed that KRAP was clearly associated with the actin filaments. Furthermore, KRAP was localized as a membrane-bound form with extracellular regions. These results together suggested KRAP might be involved in the regulation of filamentous actin and signals from the outside of the cells.     

草酸铂处理人结肠癌细胞蛋白质组分析

目的 分析草酸铂处理后人结肠癌Lovo细胞系的差异表达蛋白,从蛋白质组学角度探讨草酸铂的作用机制.方法 Lovo细胞系按完全随机法分2组,即实验组(含草酸铂培养液培养)和对照组(无草酸铂培养液培养).培养后收集细胞依次进行二维电泳分离并选择差异点,采用质谱分析鉴定差异蛋白.结果 两组双向电泳图谱分辨率高、重复性好,匹配率分别为80.16%(812/1013)和81.19%(829/1021).获取重复差异点22个,质谱分析其中10个,成功鉴定出与结肠癌相关6种蛋白:β2微球蛋白、剪接因子SFRS3、尿嘧啶DNA糖基化酶表达上调;60S核糖体蛋白P2、甘油醛3磷酸脱氢酶、鸟苷酸结合蛋白β2多肽样1表达下调.结论 草酸铂作用人结肠癌Lovo细胞系后有多种差异蛋白表达,其与免疫增强、pre-mRNA转录修饰、DNA损伤修复、调控蛋白翻译及翻译后加工、能量代谢及信号传导通路等有关.     

蟾蜍灵对结肠癌SW-480细胞polo-like kinase-1表达及细胞凋亡的影响

目的：观察蟾蜍灵对人结肠癌细胞系增殖的抑制作用，并探讨其作用机理。 方法： 采用不同浓度的蟾蜍灵作用结肠癌SW-480细胞后，采用MTT法检测细胞的恶性增殖，分别采用琼脂糖凝胶电泳和流式细胞仪检测凋亡情况，分别采用Western blotting、Northern blotting分别检测polo-like kinase-1 (PLK1)蛋白、mRNA水平。 结果： 蟾蜍灵能抑制结肠癌细胞的恶性增殖，且与浓度相关。蟾蜍灵能诱导结肠癌细胞凋亡，且呈浓度依赖性。流式细胞仪检测发现，蟾蜍灵将细胞阻滞在G2/M期。蟾蜍灵能下调结肠癌PLK1蛋白、mRNA水平，且呈药物浓度和作用时间依赖性。 结论： 蟾蜍灵有效地抑制结肠癌SW-480细胞增殖，其机制可能与其下调PLK1表达，从而诱导凋亡有关。     

Chromosomal localization of amplified c-myc in a human colon adenocarcinoma cell line with a biotinylated probe

A c-myc amplified sequence has been localized on a chromosome marker 19q+ with a biotin-labeled probe in the human colon adenocarcinoma SW480 cell line. The advantages of the technique for the localization of amplified DNA sequences are discussed.     

热休克蛋白70在人食管癌EC9706细胞凋亡过程中的表达与定位变化

目的 探讨姜黄素对人食管癌EC9706细胞凋亡的诱导作用,热休克蛋白70(HSP70)在肿瘤细胞凋亡过程中在核基质上的变化及其与凋亡调控相关蛋白的关系.方法 用细胞计数和流式细胞仪检测姜黄素对人食管癌EC9706细胞的增殖抑制作用,以光学显微镜和透射电镜观察姜黄素诱导人食管癌EC9706细胞凋亡前后的细胞结构变化,琼脂糖凝胶电泳观察人食管癌EC9706细胞凋亡前后的DNA结构变化.双向凝胶电泳和质谱鉴定分析HSP70在核基质中的存在与变化;并以Western blotting进行确证;激光扫描共焦显微镜观察HSP70在EC9706细胞凋亡过程中的定位及其与Bax、Bcl-2等基因产物的共定位关系.结果 姜黄素能显著抑制人食管癌EC9706细胞增殖并诱导人食管癌EC9706细胞凋亡,双向凝胶电泳、质谱鉴定和结果 发现并证实,HSP70在姜黄素处理前后的EC9706细胞核基质蛋白中的存在及其表达下调变化.激光扫描共焦显微镜观察结果 显示,HSP70在EC9706细胞凋亡过程中与Bax、Bcl-2等基因产物具有共定位关系,且其共定位区域发生了变化.结论 姜黄素对人食管癌EC9706细胞具有显著的凋亡诱导作用;HSP70作为一种新发现的核基质蛋白,在姜黄素诱导人食管癌EC9706凋亡过程中的表达与分布发生了显著变化.HSP70与凋亡相关基因的关系对EC9706细胞凋亡具有重要影响.     

过表达Rip2对人胰腺癌细胞Panc-1凋亡的影响

目的:观察受体相互作用蛋白2(Rip2)对人胰腺癌细胞Panc-1凋亡的影响。方法:采用Jet PRIME试剂分别将pEGFP-C2和pEGFP-Rip2质粒转染入Panc-1细胞,实验分为对照组、pEGFP-C2组和pEGFP-Rip2组。转染后培养细胞48 h,采用流式细胞术检测细胞凋亡率;Western blot检测细胞Rip2水平及凋亡相关蛋白Bax、胞浆细胞色素c(Cyt-c)和Bcl-2蛋白表达;比色法检测细胞caspase-3的活性。结果:转染pEGFP-Rip2细胞Rip2蛋白表达明显增加。流式细胞术检测表明,p EGFP-Rip2组的细胞凋亡率明显高于对照组和pEGFP-C2组。与对照组和pEGFP-C2组相比,pEGFP-Rip2组的Bax和胞浆Cyt-c蛋白表达明显升高,而Bcl-2蛋白水平则显著降低。并且,pEGFP-Rip2组细胞caspase-3活性明显高于对照组和pEGFP-C2组。结论:过表达Rip2能诱导Panc-1细胞凋亡,其作用机制可能与Rip2上调Bax以及胞浆Cyt-c蛋白表达,下调Bcl-2蛋白水平,增加caspase-3活性,从而激活内源性凋亡途径有关。     

Isolation of a novel TP53 target gene from a colon cancer cell line carrying a highly regulated wild-type TP53 expression system

We established a colon cancer cell line SW480-LOWTP53-1 carrying a wild-type TP53 transgene that is inducible under control of the lactose operon. Induction of this transgene by isopropyl-β-D-thiogalactoside (IPTG) arrests growth of the transfected cells. To investigate cellular responses related to the TP53 signaling pathway to induce growth arrest, we applied a differential display method to screen mRNAs isolated from this cell line and looked for genes whose expression was activated or suppressed after induction of wild-type TP53. Subsequent Northern blot analysis confirmed that expression of one novel gene was regulated by wild-type TP53. The cDNA, termed TP53TG1 (TP53 target gene 1), contained an open reading frame of 270 nucleotides encoding 90 amino acids. Under conditions of cellular stress (ultraviolet irradiation or exposure to bleomycin or cisplatin), expression of TP53TG1 was induced in a wild-type TP53-dependent manner, indicating that this gene is likely to play an important role in the signaling pathway of TP53 and may function in response to cellular damage. Genes Chromosomes Cancer 23:1–9, 1998. © 1998 Wiley-Liss, Inc.     

喉癌组织中的microRNA差异表达谱及miR-125a-5p抑制喉癌细胞增殖的初步研究

 目的：筛选并分析喉癌组织与周围正常喉黏膜的微小RNA(microRNAs,miRNAs) 之间的表达谱差异,为进一步研究miRNA与喉癌发生、发展的关系提供线索。方法：收集喉癌组织和癌旁正常喉黏膜标本共42对,随机选取10对标本进行miRNA微阵列基因芯片分析, 另选取32对标本进行实时荧光定量PCR （qRT-PCR）验证,获得喉癌组织中的miRNA差异表达谱。应用MTT法和克隆形成实验检测miR-125a-5p对喉癌Hep2细胞增殖的影响。结果：喉癌组织中的let-7f-5p、miR-10a-5p、miR-125a-5p、miR-144-3p、miR-195-5p、miR-203等6个miRNA在基因芯片以及qRT-PCR中表达均显著下调。与对照组相比,转染miR-125a-mimics组的喉癌Hep2细胞增殖能力受到抑制,而转染miR-125a-inhibitor组Hep2细胞增殖能力增强。结论：基因芯片与qRT-PCR结果一致;喉癌与正常喉黏膜之间存在明显的miRNA差异表达,这些miRNA的差异性表达可能与喉癌的发病、侵袭等相关。miR-125a可以抑制喉癌Hep2细胞的增殖,可能作为喉癌生物治疗的新靶点。     

人胆酸转运蛋白基因的克隆、亚细胞定位及其在肾组织中的表达

目的：克隆人肾与小肠ASBT（顶端Na+/胆汁酸协同转运蛋白）基因并比较2者的序列差别，明确ASBT蛋白在肾小管上皮的亚细胞定位及在人肾组织中的表达情况。方法:从人肾和小肠组织中提取总RNA，然后用带有8肽FLAG标签的PCR引物通过RT-PCR技术扩增ASBT全长cDNA基因并测序，并将其插入真核表达载体中构建ASBT蛋白真核表达载体，然后将其转染到肾小管上皮细胞LLC-PK1中表达并用免疫荧光-激光共聚焦显微镜观察该蛋白的亚细胞定位情况。用免疫组化技术观察ASBT在人肾组织中的表达分布。结果:序列分析结果表明肾小管ASBT基因的序列与小肠ASBT序列完全一致。Western blotting表明ASBT基因在LLC-PK1细胞中得到了正确的表达。共聚焦显微镜分析显示正常ASBT蛋白主要定位于肾小管上皮细胞膜上，与生物信息学的预测结果一致。免疫组化染色表明ASBT蛋白主要表达于人近端肾小管上皮的刷状缘侧，在间质及远端小管没有表达。结论:人肾小管ASBT基因序列与小肠ASBT相同，ASBT蛋白主要表达于近端肾小管上皮细胞管腔侧细胞膜。     

COX-2表达下调抑制人结肠癌细胞系HT-29增殖并促进凋亡

目的探讨环氧化酶-2(COX-2)表达对大肠癌细胞HT-29细胞的细胞活力、增殖和凋亡等生物学行为的影响。方法利用脂质体将siRNA COX-2及空载体转入HT-29大肠癌细胞中,并设立对照组。48 h后,real-time PCR法检测COX-2、Bcl-2、Bax和基质金属蛋白酶2(MMP2)mRNA表达;Western blot检测COX-2及p-AKT表达;CCK-8法检测细胞活力;Annexin V/PI流式双染检测细胞凋亡;流式细胞计量术检测细胞周期;划痕实验及Transwell实验分别检测细胞迁移和侵袭能力。结果与对照组及空载体组比较,COX-2抑制组COX-2蛋白及mRNA表达量显著降低(P0.01);细胞活力下降(P0.01);细胞凋亡率提高,细胞周期阻滞于G期,细胞迁移及侵袭能力降低(P0.01);Bcl-2及MMP2 mRNA表达下调(P0.01);Bax mRNA表达上调(P0.01);p-AKT蛋白表达下调(P0.01)。结论 COX-2表达量下调后能显著的抑制细胞增殖、迁移与侵袭,并诱导细胞凋亡,可能与下调p-AKT有关。     

Aberrant expression of the monocyte/macrophage phenotype in a human T cell line immortalized by HTLV-I and an adult T cell leukemia/lymphoma cell line

An HTLV-I-immortalized human T cell line (JP-2), a N -methyl- N '-nitro- N -nitrosoguanidine-treated JP-2 line (JP-2T), and an adult T cell leukemia cell line (ATL-1T) were examined morphologically and phenotypically. All of these cell lines expressed some T cell markers, including CD4, and showed rearrangement of T cell receptor (TCR) genes, but they lacked CD3 and TCR antigens and expressed some myelomonocytic markers (CD68, HL-21, CD15, CD16). JP-2 cells grew in suspension, but JP-2T and ATL-1T cells, which mostly adhered to the surface of culture vessels, showed macrophage-like morphological features and expressed more monocyte/macrophage markers (lysozyme, α₁-antitrypsin) and fibronectin. ATL-1T cells transplanted into SCID mice lost the macrophage features. These results suggest that HTLV-I infected T cells can express some macrophage features and that these cells may provide a model that will be useful in elucidating the phenotypic variability of T cell lymphomas.     

Stable expression of a Norwalk virus RNA replicon in a human hepatoma cell line

Norwalk virus (NV) is a prototype strain of the genus Norovirus in the family Caliciviridae. The human noroviruses have emerged as major agents of acute gastroenteritis in all age groups, but there are no vaccines or antiviral agents partly due to the absence of a cell culture system. We report the generation of cells expressing self-replicating NV RNA (NV replicon) following transfection of NV RNA bearing an engineered neomycin resistance gene into cell lines of human (Huh-7) or hamster (BHK21) origin. Expression of replicon RNA was significantly reduced in the presence of interferon (IFN)-alpha in a dose-dependent manner in the NV replicon-bearing cells, suggesting a role for innate immunity in the control of human norovirus replication. This stable NV replicon system should lead to new insights into norovirus replication, virus-host interactions, and approaches for the treatment of norovirus disease.     

索拉非尼对敏感人肝癌细胞株MAPK信号通路基因表达的影响

 目的：筛选对索拉非尼敏感的人肝癌细胞株,检测索拉非尼作用于敏感细胞株后MAPK信号通路基因表达谱的变化。方法：索拉非尼作用于人肝癌细胞株Huh7、 MHCC97H、 HepG2 、SMCC7721、 HepG2.2.15和PLC,流式细胞术检测肝癌细胞凋亡,CCK-8测定细胞增殖的抑制率,筛选敏感肝癌细胞株;采用实时定量PCR基因芯片,观察索拉非尼作用于敏感细胞株前后MAPK信号通路基因的表达。结果：索拉非尼作用后,流式细胞术的结果显示,凋亡较明显的细胞株为PLC和HepG2.2.15,相对不明显的细胞株为SMCC7721和MHCC97H;CCK-8测定索拉非尼对PLC、HepG2.2.15、Huh7、HepG2、MHCC97H和SMCC7721细胞的IC50值分别为5.25 μmol/L、5.30 μmol/L、6.80 μmol/L、7.01 μmol/L、11.7 μmol/L和15.0 μmol/L。对索拉非尼相对敏感细胞株和不敏感细胞株分别为PLC和SMCC7721。索拉非尼作用敏感细胞株PLC后,MAPK信号通路表达 >2.0倍的有2个,≤0.5倍的有6个。结论：PLC为对索拉非尼相对敏感的人肝癌细胞株;索拉非尼主要导致MAPK信号通路中与调控细胞周期和活化转录因子相关的基因表达发生变化。     

Signals from pancreatic mesoderm influence the expression of a pancreatic phenotype in hepatic stem-like cell line PHeSC-A2 in vitro: A preliminary study

The ex vivo generation of pancreatic cells from adult hepatic stem cells for subsequent transplantation has been proposed as a novel treatment for Diabetes mellitus. The pancreas and liver, closely related developmentally, may retain a shared (hepatopancreatic) stem cell whose plasticity could be exploited to differentiate into either lineage, dependent on environmental signals. This novel study investigated whether signals from pancreatic mesoderm could induce the differentiation of adult hepatic stem cell-like cells into pancreatic endocrine cells in vitro. A porcine hepatic stem-like cell line, designated PHeSC-A2, was co-cultured with quail pancreatic mesoderm in a Growth Factor Reduced Matrigel-Ham’s F12.ITS culture system. Immunocytochemical studies revealed insulin- and glucagon-producing cells. Assessment of nuclear morphology indicated that these endocrine cells were PHeSC-A2-derived. It is thus proposed that the PHeSC-A2 cell line has a higher level of plasticity than previously indicated. These preliminary results and assessment of published data have led to the following postulations: (a) permissive signaling from pancreatic mesoderm suffices to induce hepatic stem cells to assume a pancreatic lineage, (b) the pancreatic phenotype assumed by hepatic stem cells is a default state, (c) the differentiation capacity embodied by these cells indicates the existence of a hepatopancreatic stem cell lineage.     

全反式维甲酸对人结肠癌LoVo细胞化疗药物敏感性及Survivin基因表达的影响

目的 探讨全反式维甲酸(ATRA)对人结肠癌LoVo细胞化疗药物敏感性及Survivin表达的影响,为ATRA的临床应用提供理论依据.方法 应用流式细胞仪检测经不同浓度(10-5、10-6、10-7mol/L)的ATRA作用不同时间(24、48、72 h及第5、9、15天)后结肠癌LoVo细胞的周期变化.将细胞分为AT...     

全反式维甲酸对人结肠癌LoVo细胞化疗药物敏感性及Survivin基因表达的影响

Objective To study the effects of all-trans-retinoic acid (ATRA) on chemotherapeutics sensibility and expression of Survivin in human LoVo colon cancer cell line, and to provide a theoretical basis for clinical application of ATRA.Methods Flow cytometer (FCM) was used to detect the cell cycle of LoVo colon cancer cell line after treated with various dose of ATRA (10-5 mol/L, 10-6 mol/L and 10-7 mol/L)for 24 h, 48 h, 72 h, 5 d, 9 d and 15 d respectively.The cells were divided into ATRA group (10-6 mol/L)and control group (cultured in routine medium RPMI1640).Meanwhile, each group were divided into subgroups respectively treated with 0 g/L, 2 g/L, 4 g/L and 6 g/L 5-fluorouracil(5-FU) , or with 0 mg/L, 200 mg/L, 400 mg/L and 600 mg/L mitomycin (MMC).MTT assay was used to detect the viability of cells so as to analyze the change in chemotherapeutics sensibility.Drug interactions were analyzed according to the interaction effects.Staining with acridine orange (AO) and ethidium bromide (EB) was used to study the apoptosis in control group(RPMI1640) , ATRA group (10-6 mol/L), 5-FU group (4 g/L), MMC group (400 mg/L), ATRA (10-6 mol/L) + 5-FU (4 g/L) group and ATRA (10-6 mol/L) + MMC (400 mg/L) group.The expression of Survivin in the LoVo cell line was investigated by immunofluorescence technique.Results Compared with the control group, the percentage of cell in Go-G1 phase increased after interference with various doses of ATRA for 24 hours, peaked at 48 h, and gradually decreased afterwards, while the percentage of cells in stages S and G2-M decreased, reach the trough at 48 h, and then increased gradually.Effects of 10-6 mol/L ATRA were most significant at all time spots.Compared with control group, 10-6 mol/L ATRA reduced cell survival rate (P＜0.05),and the survival rates in control subgroups treated with various doses of 5-FU were significantly higher than those in ATRA group (all P＜0.05).In MMC-treated control group, cell survival rate with 200 mg/L MMC was lower than that in ATRA group (0.72±0.02 vs 1.03±0.13, P＜0.05) , while treatment with 400 mg/L or 600 mg/L MMC did not result in lower cell survival compared with the ATRA group (0.52±0.05 vs 0.39±0.02, 0.36±0.02 vs 0.36±0.01, all P>0.05).Positive interactions of 10-6 mol/L ATRA with 5-FU (2 g/L, 4 g/L, 6 g/L) or MMC (200 mg/L, 400 mg/L) were found.Under fluorescence microscope, cells in ATRA + 5-FU group and ATRA + MMC group showed significantly small size, pyknosis and chromatin condensation and formation of apoptotic bodies when compared with control group, ATRA group, 5-FU group and MMC group.Expression of Survivin was inhibited after 10-6 mol/L ATRA treatment for 48 h compared with control group (33.33% vs 27.96% , P＜0.05).Conclusion ATRA enhances the chemosensibility of LoVo colon cancer cell line to 5-FU and MMC,and induces cell apoptosis, potentially through inhibition of Survivin gene expression.     

穿心莲内酯对人皮肤基底细胞癌A431细胞生长、凋亡及增值细胞核抗原蛋白表达的影响

目的 探讨穿心莲内酯（AD）对人皮肤基底细胞癌A431细胞生长、凋亡及增殖细胞核抗原（PCNA）蛋白表达的影响。方法 应用酸性磷酸酶（APA）法检测细胞增殖抑制率,荧光显微镜观察细胞形态,Annexin V-FITC/PI双染法、流式细胞术（FCM）检测细胞凋亡率, Rh123染色FCM检测细胞线粒体膜电位,免疫细胞化学法检测细胞PCNA蛋白表达。结果AD呈时间、剂量依赖性抑制A431细胞生长增殖;且同一时间点50mg/L、100mg/L AD组与溶媒对照组相比差异显著（P＜0.05）。AD组作用A431细胞24h时,部分细胞核染色质出现典型凋亡形态学改变。不同浓度AD作用A431细胞24h,早期凋亡率、晚期凋亡及坏死率均随AD浓度升高而逐渐增加,且50mg/L、100mg/L AD组与溶媒对照组相比差异显著（P＜0.05）。AD作用A431 24h细胞内PCNA蛋白随AD浓度升高表达逐渐减少。AD作用A431细胞24h后,线粒体膜电位下降明显,与溶媒对照组相比较,50mg/L、100mg/L AD组差异有统计学意义（P＜0.05）。结论 AD可明显抑制A431细胞生长增殖,其抑制细胞增殖可能与下调PCNA蛋白表达有关。AD能诱导A431细胞凋亡,其凋亡机制可能与细胞线粒体膜电位下降有关。